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Old 10th June 2011, 03:35 AM   #21
tomchr is offline tomchr  United States
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Originally Posted by costis_n View Post
Now, lots of people here would advise you to go for costly exotic resistors, but i daresay that replacing them with normal carbon films will go a long way. Just swap them with equal wattage ones, in one channel only, and verify for yourself. Then, you can decide on the other channel.
I agree. A good carbon film or metal film resistor is just fine for that. The film resistors come very close to an ideal resistor. At least up to 100 MHz or so. Yaego makes a bunch that are pretty price competitive.
Carbon composite resistors on the other hand, are the old-fashioned resistors that tend to be rather noisy. In particular they have high 1/f noise.

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Old 10th June 2011, 08:17 PM   #22
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Hell all right! I'll draw the schematic.

Is there a good guide to follow for making my own schematic?

I will try to draw one, but really, by just looking at schematics in here, I'm lost, I don'T know what all the signs means.

thanks for your help.

Their also seems to be a more serious problem if I shall say: one amp play slightly louder then the other, ugh...
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Old 10th June 2011, 08:34 PM   #23
GoranB is offline GoranB  Poland
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You have an integrated amp or you have an separated power amp - preamp?
Try to replace the tubes from right to left chanell. Locate the problematic tube.
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Old 10th June 2011, 10:05 PM   #24
scott17 is offline scott17  United States
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Originally Posted by jasonthegreat View Post
Hell all right! I'll draw the schematic.

Is there a good guide to follow for making my own schematic?

I will try to draw one, but really, by just looking at schematics in here, I'm lost, I don'T know what all the signs means.

thanks for your help.

Their also seems to be a more serious problem if I shall say: one amp play slightly louder then the other, ugh...
This should help: Circuit Schematic Symbols
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Old 10th June 2011, 10:58 PM   #25
Jeb-D. is offline Jeb-D.  United States
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Quote:
Now, lots of people here would advise you to go for costly exotic resistors, but i daresay that replacing them with normal carbon films will go a long way. Just swap them with equal wattage ones, in one channel only, and verify for yourself. Then, you can decide on the other channel.
Though I'm sometimes hesitant to admit (in fear of being flamed), I tend to prefer the normal carbon films over other resistors that I have tried (which includes some of the fancy ones). Their 3 band color code is also a plus in my book.
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Old 11th June 2011, 12:11 PM   #26
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Originally Posted by Jeb-D. View Post
Though I'm sometimes hesitant to admit (in fear of being flamed), I tend to prefer the normal carbon films over other resistors that I have tried (which includes some of the fancy ones). Their 3 band color code is also a plus in my book.

Absolutely!

A bit of sense in a hobby plagued by 'Fashion'!

IMO--way too much emphisis is placed on component type, rather than the design and implementation!

A Cruddy design and layout will still be cruddy no matter how many boutique and stupidly expensive parts are used!

Get it as perfect as possible using the standard range resistors/caps --Then, and ONLY then, play with the exotic parts....

I'm always suspicious of designs Ive seen, that specify that you MUST use a certain boutique cap or resistor, as in the past Ive built the odd one like this, and found that the DESIGN was at fault in some way or other.....

Last edited by Alastair E; 11th June 2011 at 12:13 PM.
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Old 13th June 2011, 03:54 PM   #27
tomchr is offline tomchr  United States
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Quote:
Originally Posted by Jeb-D. View Post
Though I'm sometimes hesitant to admit (in fear of being flamed), I tend to prefer the normal carbon films over other resistors that I have tried (which includes some of the fancy ones). Their 3 band color code is also a plus in my book.
I think what you're referring to are carbon composite resistors not carbon film. Carbon film is a conductive film evaporated onto a ceramic tube and trimmed to get the desired resistance. Same process as with metal film. The carbon composite resistors are carbon molecules that are squished/sintered together to form the resistive element. They tend to have high 1/f noise, but supposedly have very low inductance.

~Tom
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Old 13th June 2011, 04:44 PM   #28
Bigun is offline Bigun  Canada
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I sense you are anxious to fix the amp but are held back because you aren't comfortable or confident about the technical aspects of it ? I think you will be vastly happier if you resolve yourself to take some effort to understand more of the technical aspects instead of relying on folklore about component choices. If you work out the schematic for yourself and read up a bit to see how others build DIY tube amps you will gain a lot.

The main thing - SAFETY first. These amps can kill. Never go inside it when it's plugged into the AC outlet, and make sure all capacitors are discharged. They should have resistors across them to ensure a safe and slow discharge on power-off. If not, there can be enough juice in the power supply caps to end your music days.

with a SET and no feedback the tubes can have different gains so the volume in one channel can be slightly higher than the other - that's normal.

I have a bag of 6B4G tubes waiting for a project, I bought them because I believe they are good tubes and capable of being used to make a nice sounding amp.
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Old 13th June 2011, 11:34 PM   #29
Jeb-D. is offline Jeb-D.  United States
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Quote:
Originally Posted by tomchr View Post
I think what you're referring to are carbon composite resistors not carbon film. Carbon film is a conductive film evaporated onto a ceramic tube and trimmed to get the desired resistance. Same process as with metal film. The carbon composite resistors are carbon molecules that are squished/sintered together to form the resistive element. They tend to have high 1/f noise, but supposedly have very low inductance.

~Tom
I understand your reason for doubt, but I do mean carbon film. I find them to be more vibrant sounding than metal film, but less noisy than carbon comp (and don't have the drift problem either).
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Old 14th June 2011, 01:06 AM   #30
kevinkr is offline kevinkr  United States
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Originally Posted by Jeb-D. View Post
I understand your reason for doubt, but I do mean carbon film. I find them to be more vibrant sounding than metal film, but less noisy than carbon comp (and don't have the drift problem either).
Interesting, to each their own I guess. Could be a system thing or design philosophy. (Different goals) I actually avoid them mostly because I have run across a few that seemed to have measurable linearity issues at least in the context of the designs I do.. Like CC they do have a significant voltage coefficient and generate a lot more 2nd harmonic than most metal films (have run into some bad ones here as well) - wonder if this characteristic warms the sound up a bit?
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